With the recent wide-spread of smart phones and the like, the use of pressure sensors enabling a sensing operation in a height direction has increased. There has been proposed a piezo-resistive pressure sensor which detects a variation of resistance of a piezo-resistive element as a variation of pressure. For example, there is known a pressure sensor including a base substrate, a cap substrate which is formed therein with a concave portion to define a space between the concave portion and the base substrate by being bonded to the base substrate, a membrane which is formed in the space using a portion of the base substrate, and an impurity diffusion region serving as a pressure sensor element formed in the membrane. In this pressure sensor, the membrane is displaced in response to a pressure applied thereto and a variation of resistance of the impurity diffusion region in response to the displacement is measured to detect the pressure.
However, a piezo-resistive element is susceptible to a change in ambient temperature and is likely to result in a deviation in detection precision under varying ambient temperature. This requires a correction on a pressure detected in the pressure sensor using the piezo-resistive element. In addition, a sensor having a 3D structure with at least two substrates bonded to each other has a problem of high costs and an increased size of the pressure sensor.